As a method of washing clothes made from wool, for example, a washing method called dry cleaning has widely been known. The dry cleaning is a method of cleaning clothes using a petroleum solvent or an organic solvent as a cleaning liquid. The dry cleaning is the washing method capable of preventing loss of shape, shrinkage, swelling, and the like of the clothes while washing clothes conveniently. This is one of reasons of the widespread of the dry cleaning.
More specifically, contaminations adhered to clothes are usually of water-soluble contaminations such as sweat, foods, and mud. In order to perfectly clean such water-soluble contaminations, it is necessary to wash the clothes with water. However, when the clothes made from wool are washed with water, a scale formed on a surface of fibers (wool) is damaged to change a fabric to a felt-like one. When the fabric becomes feltish, the clothes are hardened to loose the original texture and to be difficult to wear. However, when the petroleum solvent or the like is used as the cleaning liquid, the above-described fabric change does not occur. Therefore, the dry cleaning has widely been employed as the clothes washing method.
However, in the case where the petroleum solvent is used as the cleaning liquid, the water soluble contaminations adhered to the clothes are not cleaned perfectly, and yellowing and the like of the clothes can occur later on. That is, the dry cleaning is employed for the purpose of avoiding the risk of damage on clothes though it is necessary to wash the clothes with water in order to perfectly clean the contaminations of the clothes.
The washing method employed for conventional washing machines can be divided into two types. One of them is a washing method utilizing a rotating current of a washing liquid (see, for example, Patent Publication 1), and the other is a washing method utilizing a mechanical force (see, for example, Patent Publications 2 and 3).
With the washing method utilizing the rotating current of cleaning liquid, a washing tub is rotated about a rotation shaft disposed in a substantially vertical direction, so that the cleaning liquid is rotated in a substantially horizontal direction inside the washing tub. Clothes are cleaned by means of the rotating current of cleaning liquid. With the washing method utilizing the mechanical force, a washing tub is rotated about a rotation shaft disposed in a substantially horizontal direction, so that clothes placed in the washing tub are moved upward along an inner wall surface of the washing tub and then fall down. The clothes are cleaned by means of impact caused when the clothes fall on the inner wall surface of the washing tub. That is, with the washing method utilizing the rotating current of cleaning liquid, the contaminations are separated when the clothes are twisted round by means of the rotating cleaning liquid. With the washing method utilizing the mechanical force, the contaminations are separated by means of the impact applied on the clothes. In both washing methods, burden on the fabrics is large, and, though a certain cleaning effect is achieved by the washing methods, the fabrics are steadily damaged.
Conventional washing apparatuses and washing methods are disclosed in Patent Publications 1 to 10 listed below. Particularly, Patent Publication 4 (JP-A-4-61893) discloses a washing method for flipping a laundry article by means of a jet current and a washing apparatus for performing the washing method. As disclosed in Patent Publication 4, the washing apparatus is provided with an outer barrel (1) and an inner barrel (4). The laundry article is placed in the inner barrel (4), and the outer barrel (1) is filled with a washing liquid. A propelling wing (18) is disposed in a space communicated with an interior of the outer barrel (1). When the propelling wing (18) is rotated, a strong swirling current of the washing liquid is generated in the outer barrel (1). The laundry article is twisted round by the swirl of washing liquid, so that the contaminations are cleaned.
As explained above, Patent Publication 4 discloses that the contaminations of the laundry article thrown into the washing liquid filled in the washing tub are cleaned by the strong current of the washing liquid. It is said in Patent Publication 4 that the washing method causes little damage on the laundry article and exhibits a strong detergency (see page 4, fourth line of upper right column to lower left column). However, since the washing method disclosed by Patent Publication 4 utilizes the strong swirl of the washing liquid generated by the propelling wing (18) as explained in the foregoing, the washing method is far from being harmless for the laundry article. More specifically, with the washing method disclosed by Patent Publication 4, a swirling jet current turning around repeatedly in the vertical direction of the inner barrel is generated. This swirling jet current moves the laundry article vertically. The laundry article is cleaned in such a manner that the laundry article is pressed against an inner upper surface and an inner lower surface of the inner barrel to be rubbed and, at the same time, twisted round and then untwisted. With such washing method, the damage on the laundry article is not small at all, and it is apparent that the laundry article is strongly twisted so that the fibers constituting the laundry article are damaged.
Patent Publication 1: JP-A-2002-58892
Patent Publication 2: JP-A-2003-260290
Patent Publication 3: JP-A-2001-269495
Patent Publication 4: JP-A-4-61893
Patent Publication 5: JP-A-4-164494
Patent Publication 6: JP-A-11-169579
Patent Publication 7: JP-A-60-246790
Patent Publication 8: JP-UM-B-35-31858
Patent Publication 9: JP-A-11-267391
Patent Publication 10: JP-A-6-238086